Good question: I had to innovate!
I first cut an appropriately measured length of 1" PVC pipe. Next, I worked this tube under the carpet from the backseat side, along the right side of the hump, and up to an opening in the carpet located just a few inches in under the rear of the center console. (I'd already loosened the center console to ease getting the new wires from the head unit to that point.)
From here it was simply a matter of sliding the relatively stiff speaker wires through my makeshift PVC "tunnel", pulling the tube back out, making the required connections, and reassembling the car
NOTE: The toughest part about this method was figuring out how to correctly reassemble the cable-assembly that opens and closes the fresh air vent on the center console. (As soon as you loosen the back of the console, this "Rube Goldberg"-inspired setup comes apart.) I've had my console apart before (installing a cell phone car kit last year), so I knew the procedure. I was able to get things back together in minutes; but that wasn't the case when I installed the phone last year. Then it took a LONG time for my pea-brain to figure out the procedure.
